Our Projects

Hamilton, Ont. – Randle Reef Sediment Remediation Project

Hamilton Port Authority

Riggs Engineering was engaged by Arcadis US Inc. for the marine and structural engineering components of an engineered containment facility (ECF) for the Randle Reef Sediment Remediation Project in Hamilton Harbour, on Lake Ontario, in Hamilton, Ontario. The ECF is designed to contain contaminated sediments to be dredged from the harbour and for future port development.

The ECF is comprised of double sheet pile walls to minimize the structural footprint, to maximize containment and to effectively seal in the sediments with a barrier anchor wall. Analyses included limit equilibrium and beam on elastic foundation analysis of sheet pile structures using various steel sheet pile and finite element analyses software. Methods were investigated to improve the wall loadings to economize the design selection of the sheet piling by replacing the weak clay where practical.

The lateral stiffness of the structure was assessed using a 2D plain strain finite element code. The stages of placing sediment inside the structure and of pre-loading the sediments for strength gain presented unique challenges. In the undrained condition, the stiffness of the double wall structure proved inadequate to resist the stresses imposed during the preloading. To address this, the preload is to be applied in stages with material strength gain assessed at the end of each stage.